This study examined the effects of stressful environments on physiological and affective functioning among 131 maltreated school-aged children attending a summer day camp. Sixty-six nonmaltreated children also attending the camp served as a comparison group. Salivary cortisol measures were obtained daily at 10:00 , a.m. and at 4:00 p.m. Depression was measured using the Child Depression Inventory. Children with scores of 19 or higher were classified as depressed. Internalizing and externalizing behavior problems were determined from the Teacher Report Form of the Child Behavior Checklist. Children with t scores of 70 or higher were classified as having clinical levels of these problems. Maltreated children had slightly elevated afternoon cortisol concentrations, but their morning concentrations did not differ significantly from those of nonmaltreated children. Neither clinical levels of depression, internalizing, or externalizing problems were predictive of the elevated afternoon values. Depression among maltreated children was, however, associated with altered activity of the hypothalamic-pituitary-adrenocortical (HPA) axis. Depressed maltreated children had lower morning cortisol concentrations compared to nondepressed maltreated children and were more likely to show a rise rather than the expected decrease in cortisol from morning to afternoon. These data replicated earlier findings. There was no evidence that depressed, nonmaltreated children exhibited this change in diurnal cortisol activity.